Demineralized bone matrix and calcium-phosphate cement in bone regeneration in rats

Purpose: To compare bone regeneration in critical-sized defects in rat calvarium using demineralized bone matrix and calcium phosphate cement. Methods: Thirty Wistar rats were divided into 3 groups of 10 animals each. Two defects of 5-mm were made in the parietal bones of each animal. Group I had calcium phosphate cement placed in the experimental defect, Group II had filled with demineralized bone matrix and Group III had with the combination of the matrix and cement in equal parts. All animals had one defect left unfilled to serve as controls. Five animals in each group were sacrificed at 4 and 8 weeks. Histomorphometric analysis was used to quantify the amount of new bone within the defects. Results: The results showed that demineralized bone matrix-treated defects had significantly more new bone at 4 weeks compared to calcium phosphate cement-treated defects (p=0.03) and also had significantly more new bone at 8 weeks compared to unfilled defects (p=0.04). Conclusions: The demineralized bone matrix was superior to calcium phosphate cement in bone regeneration. It seems that calcium phosphate cement acted by inhibiting the osteogenesis when associated with a demineralized bone matrix and this combination should not be recommended.(AU)

Use of calcium phosphate cement scaffolds for bone tissue engineering: in vitro study / A utilizacao do cimento de fosfato de calcio como arcabouco para engenharia de tecido osseo: estudo in vitro

Purpose: To evaluate the ability of macroporous tricalcium phosphate cement (CPC) scaffolds to enable the adhesion, proliferation, and differentiation of mesenchymal stem cells derived from human bone marrow. Methods: Cells from the iliac crest of an adult human donor were processed and cultured on macroporous CPC discs. Paraffin spheres sized between 100 and 250µm were used as porogens. Cells were cultured for 5, 10, and 15 days. Next, we assessed cells' behavior and morphology on the biomaterial by scanning electron microscopy. The expression levels of the BGLA and SSP1 genes and the alkaline phosphatase (ALP) activity were quantified by the quantitative real-time polymerase chain reaction technique (QT-PCR) using the fluorophore SYBR GREEN®. Results: QT-PCR detected the expression of the BGLA and SSP1 genes and the ALP activity in the periods of 10 and 15 days of culture. Thus, we found out that there was cell proliferation and differentiation in osteogenic cells. Conclusion: Macroporous CPC, with pore sized between 100 and 250µm and developed using paraffin spheres, enables adhesion, proliferation, and differentiation of mesenchymal stem cells in osteogenic cells and can be used as a scaffold for bone tissue engineering.(AU)

Objetivo: Avaliar a capacidade de suportes tridimensionais macroporosos de cimento de fosfato de calcio (CFC), de permitir a adesao, proliferacao e diferenciacao de celulas-tronco mesenquimais derivadas da medula ossea humana. Metodos: celulas obtidas da crista iliaca de um doador humano adulto foram processadas e cultivadas sobre suportes de CFC, macroporosos, que tiveram como corpo gerador de poros, microesferas de parafina, com tamanho entre 100 e 250µm. Os periodos de cultura estabelecidos foram de cinco, 10 e 15 dias. Apos estes periodos, o comportamento e a morfologia das celulas junto ao biomaterial foram avaliados por meio de Microscopia Eletronica de Varredura. Os niveis de expressao dos genes BGLA e SSP1 bem como a atividade da Fosfatase Alcalina (ALP) foram quantificados pela tecnica de PCR em Tempo Real (QT-PCR) utilizando o fluoroforo SYBR Green®. Resultados: O QT-PCR detectou a expressao dos genes BGLA e SSP1 e a atividade da fosfatase alcalina nos periodos de 10 e 15 dias de cultura. No periodo de cinco dias, nao foi observada a expressao de nenhum dos genes investigados. Conclusao: O CFC, macroporoso, com tamanho de poros entre 100 e 250µm, criados por meio da utilizacao de microesferas de parafina, permite a adesao, proliferacao e diferenciacao de celulas-tronco mesenquimais em celulas osteogenicas, podendo ser utilizado como arcabouco para engenharia de tecido osseo.(AU)